Anti-scratch film for flexible display

ABSTRACT

An anti-scratch film, including a film base and an anti-scratch layer on one side of the film base. The anti-scratch layer includes a plurality of protrusions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/011,732, filed Aug. 27, 2013, which claims priority to and thebenefit of Korean Patent Application No. 10-2012-0136844, filed on Nov.29, 2012 in the Korean Intellectual Property Office, the entire contentsof which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a functional film for a display, andmore particularly, to an anti-scratch film for a flexible display.

BACKGROUND

With the development of an information-oriented society, research onflat panel displays has gradually increased according to variousdemands. The flat panel displays include a plasma display panel (PDP), aliquid crystal display (LCD), and an organic light emitting display(OLED). In particular, OLEDs receive attention as a next-generationdisplay device because of features such as a light weight, a thinstructure, and low power consumption, but the LCD is widely usedcurrently because of features such as a large area and a long lifespan.

Recently, a flexible display device that implements the various flatpanel displays on a substrate made of a flexible material has receivedattention. There are advantages in that the flexible display device isthin and light, and can be bent or curved so as to be manufactured invarious forms, and as a result, currently, the flexible display deviceis estimated as a next-generation technology in a flat panel displaymarket.

A flat panel display has a structure in which a separate anti-scratchlayer is interposed at the outermost side of the display device, inorder to prevent the display from being damaged due to external contact.

FIG. 1 shows a diagram illustrating a configuration of an anti-scratchfilm 10 in the related art. The anti-scratch film in the related art mayinclude a film base 11 and an anti-scratch layer 20 on the film base 11.

The anti-scratch layer 20 may be formed by coating a material havinghigh hardness such as silicon oxide (SiO_(x)) or glass on the film base11.

The anti-scratch layer 20 serves to protect the display device fromexternal contact such as a touch input pen or a human hand.

Since the anti-scratch layer 20 has high hardness, the anti-scratchlayer 20 has an advantage of protecting the display device from externalcontact, but since the anti-scratch layer 20 has a brittlecharacteristic when bent, the anti-scratch layer 20 is not typicallyused for a display device having a bending characteristic such as theflexible display device

SUMMARY

Aspects of embodiments of the present disclosure are directed toward aneffort to provide an anti-scratch film and a manufacturing methodthereof capable of being used for a display device having a bendingcharacteristic such as a flexible display device.

An embodiment of the present disclosure provides an anti-scratch film,including: a film base; and an anti-scratch layer on one side of thefilm base, in which the anti-scratch layer includes a plurality ofprotrusions.

The film base may be formed with a transparent material.

An adhesive layer may be further included on the other side of the filmbase.

The anti-scratch layer may include at least one of AlO_(x), SiO_(x),SiN_(x), and SiON.

The shape of each protrusion of the plurality of protrusions may be anyone of a lens shape, a pyramidal shape, a conical shape, a prismaticshape, or a cylindrical shape.

A height of each protrusion of the plurality of protrusions may be from0.1 μm to 100 μm.

A diameter of each protrusion of the plurality of protrusions may be 10μm to 1 mm, with a longest radius on the base side of the protrusion.

A distance between adjacent protrusions may be from 10 μm to 1 mm.

An embodiment of the present disclosure provides a method ofmanufacturing an anti-scratch film, including forming protrusions on oneside of a film base.

The forming of the protrusions may include coating a material forforming the protrusions on one side of the film base; forming aphotoresist pattern on the material for forming the protrusions;exposing and developing the material for forming the protrusions withthe photoresist pattern; etching the material for forming theprotrusions with the photoresist pattern; and removing the photoresistpattern.

The forming of the protrusions may include forming a mask pattern on oneside of the film base; and depositing a material for forming theprotrusions.

Yet another embodiment of the present disclosure provides a displaydevice, including: a substrate; a display element layer on thesubstrate; an encapsulation layer on the display element layer; and ananti-scratch film on the encapsulation layer, in which the anti-scratchfilm comprises a film base and an anti-scratch layer comprising aplurality of protrusions on one side of the anti-scratch film.

The display element layer may include a first electrode; an active layeron the first electrode; and a second electrode on the active layer.

The active layer may be an organic emission layer.

The active layer may be a liquid crystal layer.

Since an anti-scratch layer according to some embodiments has astructure capable of dispersing bending stress which is applied to theanti-scratch layer while the flexible display device is bent, theanti-scratch layer can be used even for a display device having abending characteristic such as the flexible display device.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram illustrating a configuration of an anti-scratchfilm in the related art.

FIG. 2 shows a cross-sectional view illustrating an anti-scratch filmaccording to an embodiment of the present disclosure.

FIG. 3 shows a perspective view illustrating an anti-scratch filmaccording to an embodiment of the present disclosure.

FIG. 4A shows a diagram illustrating a bending moment applied to theanti-scratch film in the related art.

FIG. 4B shows a diagram illustrating a bending moment applied to theanti-scratch film according to an embodiment of the present disclosure.

FIG. 5 shows a diagram illustrating an anti-scratch film according toanother embodiment of the present disclosure.

FIG. 6 shows a diagram illustrating an anti-scratch film according toanother embodiment of the present disclosure.

FIG. 7 shows a diagram illustrating a manufacturing method of theanti-scratch film according to an embodiment of the present disclosure.

FIG. 8 shows a diagram illustrating a case where the anti-scratch filmaccording to an embodiment of the present disclosure is applied to anorganic light emitting display.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described inmore detail with reference to the accompanying drawings.

Although the present disclosure can be modified in various ways and haveseveral embodiments, specific embodiments are illustrated in theaccompanying drawings and are described in the specification. However,the scope of the present disclosure is not limited to the specificembodiments described herein and should be construed as including allchanges, equivalents, and substitutions included in the spirit and scopeof the present disclosure.

In the specification, specific structural or functional descriptions areonly exemplified to describe embodiments. The embodiments of the presentdisclosure can be implemented in various suitable forms, and thus thepresent disclosure is not limited to these embodiments. It should beunderstood that the present disclosure contains all changes,equivalents, and substitutions included in the spirit and the scope ofthe present disclosure.

It will be understood that when an element is simply referred to asbeing ‘connected to’ or ‘contacted to’ another element without beingreferred to as ‘directly connected to’ or ‘directly contacted to’another element in the present disclosure, it may be ‘directly connectedto’ or ‘directly contacted to’ another element or be connected to orcoupled to another element, having the one or more other elementsintervening therebetween.

When an element is referred to as being ‘directly connected to’ or‘directly contacted to’ another element, another element intervening isnot present therebetween. Other expressions describing the relationshipsamong the elements, for example, ‘between’, ‘directly between’ or‘adjacent to’ and ‘directly adjacent to’ may also be interpretedsimilarly.

Terms used in the specification are just used to describe illustrativeembodiments and are not to be construed as limiting the presentdisclosure. A singular expression includes plural expressions as long asthe expressions do not have an apparently different contextual meaning.

In this specification, terms such as ‘comprise’, ‘include’, or ‘have’are used to designate presence of particular features, figures, steps,operations, elements, parts, or combinations thereof and it should beunderstood that additional features, figures, steps, operations,elements, parts, or combinations thereof, may also be included. Unlessotherwise defined, all terms used herein, which include technical orscientific terms, have the same meanings as those generally appreciatedby those skilled in the art. It should be understood that terms definedin advance, which are generally used have the same meanings ascontextual meanings of associated techniques, if not explicitly definedin this application, the terms are not ideally or excessively analyzedas to their formal meanings.

Like reference numerals refer to like elements throughout thespecification. Further, in the drawings, size and thickness of eachelement are schematically illustrated for convenience of description,and the present disclosure is not necessarily limited to thoseillustrated in the drawings.

In the drawings, the thicknesses of layers and regions are enlarged forclarity. In the drawings, the thicknesses of some layers and regions areexaggerated for convenience of description.

In this specification, the terms “film” or “films” may refer to layers,sheets, or plates having regular or substantially regular widths andthicknesses.

FIG. 2 shows a cross-sectional view illustrating an anti-scratch filmaccording to an embodiment of the present disclosure. FIG. 3 shows aperspective view illustrating an anti-scratch film according to anembodiment of the present disclosure.

Referring to FIGS. 2 and 3, an anti-scratch film 100 according to anembodiment of the present disclosure may include a film base 110 havingan anti-scratch layer 120 on one side of the film base. The anti-scratchlayer 120 may include a plurality of protrusions 121.

The film base 110 may be made of a transparent material, but thematerial is not limited thereto and may be translucent or coloredaccording to an optical requirement.

The film base 110 may be formed by using a flexible material. Athickness of the film base 110 is not particularly limited, but may bein the range of from 25 μm to 500 μm.

The film base 110 may use a film which is selected from knowntransparent material films, and it is not particularly limited. Thetransparent material films include, but are not limited to a polyesterfilm, a polyethylene film, a polypropylene film, a tri-acetyl cellulosefilm, a polyvinyl chloride film, a polyvinyl alcohol film, a polyimidefilm, a cyclo-olefin resin film, a polycarbonate film, a polyethyleneterephthalate film, a polyethylene naphthalate film, a polyether sulfonefilm, a polyimide film, an epoxy resin film, a phenol resin film, amelamine resin film, a polyurethane film, and/or an acrylic resin film.

The anti-scratch layer 120 may be formed on one side of the film base110. The anti-scratch layer 120 may include the plurality of protrusions121, and the plurality of protrusions 121 on the anti-scratch layer 120may be separated from each other with island shapes.

A height H of each of the protrusions 121 may be from 0.1 μm to 100 μm,and a diameter D (with a longest radius on the base side of each of theprotrusions 121, e.g. the protrusion 121 may get narrower toward thetop) may be from 10 μm to 1 mm. Further, a distance L between adjacentprotrusions 121 may be from 10 μm to 1 mm.

In an embodiment, the diameter D, with the longest radius on the baseside of the protrusion 121, is be formed with a set maximum size so thateach protrusion 121 may be maintained in a flat or substantially flatstate, even when the anti-scratch layer 120 is bent with a set radius ofcurvature.

In an embodiment, the distance L between the protrusions 121 is bemaintained to have a smaller distance than a thickness of a touch inputpen or a human nail, in order to protect the display device fromexternal contact.

The height H and the size or diameter D of each of the protrusions 121,and the distance L between adjacent protrusions 121, may have set valuesaccording to the radius of curvature of the flexible display.

The plurality of protrusions 121 may contain at least one of aluminumoxide (AlO₂), aluminum nitride (AlN), aluminum oxynitride (AlON),silicon oxide (SiO₂), silicon nitride (SiN), and/or oxidized siliconnitride (SiON). In an embodiment, the protrusions 121 are formed with amaterial having a set minimum hardness, in order to protect the displaydevice from external contact.

An adhesive layer 130 for attaching the film base 110 to the displaydevice may be disposed on the other side of the film base 110. The otherside of the film base 110 refers to a side of the film base 110 wherethe anti-scratch layer 120 is not formed, that is, a side of the filmbase 110 facing oppositely away from the side where the anti-scratchlayer 120 is formed. The adhesive layer 130 may include an adhesivelayer 131 and a releasing sheet 132.

The adhesive layer 131 may use an adhesive suitable for optical use(transparency), and the adhesive may use a urethane-based adhesiveand/or a silicon-based adhesive. A thickness of the adhesive layer 131may be in the range of from 10 μm to 60 μm.

The adhesive layer 130 may include a separate releasing sheet 132, forconvenience of storage.

The anti-scratch film 100 according to an embodiment of the presentdisclosure may disperse stress applied to the anti-scratch layer 120 byforming the anti-scratch layer 120 with the plurality of protrusions 121having island shapes as illustrated in FIG. 2.

Stress refers to a resistance or deforming force in a material generatedwhen external force is applied to any material. The stress iscontinuously increased as the external force is increased, but since thematerial has a limit capable of resisting the stress, the materialbreaks when the material reaches a unique stress limit. That is, thelarger the stress limit is, the stronger the material may be.

A magnitude of the stress may be represented by a magnitude of theexternal force applied per unit area, which is called a unit stress.Hereinafter, the term “stress” refers the unit stress unless otherwisenoted.

Meanwhile, when a bending moment capable of bending the material isapplied, the stress applied to the material is called “bending stress”.

FIG. 4A shows a diagram illustrating a bending moment M1 applied to theanti-scratch film in the related art, and FIG. 4B shows a diagramillustrating a bending moment M2 applied to the anti-scratch filmaccording to an embodiment of the present disclosure.

As illustrated in FIG. 4A, when the bending moment M1 is applied to theanti-scratch film in the related art, bending stress BS applied to theanti-scratch layer 20 is highest at P1.

Since a bending stress limit of silicon oxide (SiO_(x)) used for theanti-scratch layer 20 is smaller than a bending stress limit of aflexible substrate, when the bending moment M1 reaches or exceeds acertain magnitude, the anti-scratch layer 20 is brittle at P1, where thebending stress BS is concentrated.

However, the anti-scratch film according to the present disclosure has astructure in which bending stress BS applied to P2 of the anti-scratchlayer 120 is laterally dispersed, even though the bending moment M2 isapplied as illustrated in FIG. 4B, and as a result, the anti-scratchlayer 120 is not brittle or is less brittle. That is, since the ratio ofthe diameter D of each protrusion 121 to the radius of curvature wherethe anti-scratch layer 120 is bent, is very small, each protrusion 121may be maintained in an almost flat state.

In FIGS. 2 and 3, the shape of the protrusion 121 is illustrated as asquare column, but is not necessarily limited thereto, and the shape ofthe protrusion 121 may be formed in various suitable shapes such as alens shape, a pyramid shape, a conical shape, a cylindrical shape, apyramidal shape having a flat apex, or a conical shape having a flatapex.

The shape of the protrusion 121 may be formed in a shape selectedaccording to a particular use of the anti-scratch film, a bendingdirection of the display device, and/or a radius of curvature.

FIGS. 5 and 6 are diagrams illustrating an anti-scratch film accordingto another embodiment of the present disclosure.

As illustrated in FIGS. 5 and 6, the anti-scratch films 200 and 300include film bases 210 and 310, and anti-scratch layers 220 and 320 onone side of the film base. The anti-scratch layer 220 may include aplurality of protrusions 221 and 321, and the shapes of the protrusions221 and 321 may be formed in lens shapes (see FIG. 5) or pyramid shapeshaving flat apexes (see FIG. 6).

FIG. 7 is a diagram illustrating a manufacturing method of ananti-scratch film according to an embodiment of the present disclosure.

A manufacturing method of an anti-scratch film 400 according to anembodiment of the present disclosure may include preparing a film base410 and forming an anti-scratch layer including a plurality ofprotrusions on one side of the film base 410.

Referring to FIG. 7, the forming of the anti-scratch layer including theplurality of protrusions may include coating a material 420 for formingthe protrusions on one side of the film base 410 (see FIG. 7A), forminga photoresist pattern 450 on the material 420 for forming theprotrusions (see FIG. 7B), exposing and developing the material 420 forforming the protrusions with the photoresist pattern 450 (see FIG. 7C),etching the material 420 for forming the protrusions with thephotoresist pattern 450 (see FIG. 7D), and removing the photoresistpattern 450 (see FIG. 7E).

The coating of the material 420 for forming the protrusions on one sideof the film base 410 (see FIG. 7A) may include coating at least one ofaluminum oxide (AlO₂), aluminum nitride (AlN), aluminum oxynitride(AlON), silicon oxide (SiO₂), silicon nitride (SiN), and oxidizedsilicon nitride (SiON).

A method of coating the material 420 for forming the protrusions mayinclude a spin coating process, a printing process, and/or a sputteringprocess.

The etching of the material 420 for forming the protrusions with thephotoresist pattern 450 (see FIG. 7D) may use a dry etching processand/or a wet etching process.

The forming of the anti-scratch layer 420 including the plurality ofprotrusions may include forming a mask pattern on one side of the filmbase 410 and depositing a material for forming the protrusions.

A method of depositing the material for forming the protrusions may usea chemical vapor deposition (CVD) process, an atomic layer deposition(ALD) process, a plasma enhanced chemical vapor deposition (PECVD)process, a high density plasma-chemical vapor deposition (HDP-CVD)process, a vacuum deposition process, or the like.

FIG. 8 is a diagram illustrating an organic light emitting displayincluding the anti-scratch film according to an embodiment of thepresent disclosure.

An organic light emitting display 500 including the anti-scratch filmmay include a substrate 510, an organic light emitting diode on thesubstrate, an encapsulation layer for sealing the organic light emittingdiode, and an anti-scratch film on the encapsulation layer.

The substrate 510 may be made of various suitable materials such as aglass substrate, a quartz substrate, and a transparent resin substrate,and may be formed by using a flexible material. The transparent resinsubstrate which may be used as the substrate 510 may contain a polyimideresin, an acrylic resin, a polyacrylate resin, a polycarbonate resin, apolyether resin, a polyethylene terephthalate resin, a sulfonic acidresin, or the like.

The organic light emitting diode may include a plurality of firstelectrodes 521 on the substrate 510, a pixel defining layer 522 formedbetween the first electrodes 521 and overlapped with ends of the firstelectrodes 521 to divide the first electrodes 521 by a pixel unit, anorganic layer 523 on the first electrode 521 divided by the pixeldefining layer 522, and a second electrode 524 on the organic layer 523.

The encapsulation layer may be formed with a multilayered thin filmstructure where an organic layer and an inorganic layer are alternatelylaminated in one or more pairs.

The organic layer may include epoxy, acrylate, urethane acrylate,polyurea, polyacrylate,perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA),3,3′,4,4′-biphenyl-tetracarboxylic acid dianhydride (BPDA), and/orpyromellitic dianhydride (PMDA).

The inorganic layer may include of silicon nitride, aluminum nitride,zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride,silicon oxide, aluminum oxide, and/or titanium oxide.

In addition, inorganic thin film materials or organic thin filmmaterials which are known in the art may be used as the materials of theinorganic layer and/or the organic layer of the present disclosure,respectively.

The organic layer and the inorganic layer may be formed by using a spincoating process, a printing process, a sputtering process, a chemicalvapor deposition (CVD) process, an atomic layer deposition (ALD)process, a plasma enhanced chemical vapor deposition (PECVD) process, ahigh density plasma-chemical vapor deposition (HDP-CVD) process, and/ora vacuum deposition process.

The anti-scratch film may be laminated on the encapsulation layer 530.The anti-scratch film may include a film base 541 and an anti-scratchlayer 542 including a plurality of protrusions on the film base 541. Asthe anti-scratch film, the anti-scratch film according to an embodimentof the present disclosure may be used. An adhesive layer for adhering tothe encapsulation layer may be further included at the bottom of thefilm base 541.

The anti-scratch film may be used in a flexible flat panel display andthe like, in addition to the organic light emitting display. Theflexible flat panel display may include a liquid crystal display and thelike.

As described above, the anti-scratch film including the plurality ofprotrusions is only exemplified, and those skilled in the art canunderstand that the scope of the present disclosure may include variousmodifications and equivalent embodiments therefrom.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure and thefollowing claims. Accordingly, the various embodiments disclosed hereinare not intended to be limiting.

What is claimed is:
 1. A display device comprising: a substrate; adisplay element layer on the substrate; an encapsulation layer on thedisplay element layer; and an anti-scratch film on the encapsulationlayer, wherein the anti-scratch film comprises a film base and aplurality of anti-scratch protrusions directly on one side of the filmbase, the plurality of anti-scratch protrusions forming an outermostsurface of the display device, wherein adjacent ones of the plurality ofanti-scratch protrusions are spaced from each other such that a portionof the film base is exposed between the adjacent ones of the pluralityof anti-scratch protrusions, and wherein the anti-scratch protrusionscomprise a material different from a material of the film base.
 2. Thedisplay device of claim 1, wherein each of the plurality of anti-scratchprotrusions comprises only a single inorganic material.
 3. The displaydevice of claim 2, wherein the inorganic material comprises at least oneselected from the group consisting of an oxide, a nitride, and anitric-oxide.
 4. The display device of claim 1, wherein the film basecomprises an organic material.
 5. The display device of claim 4, whereinthe organic material comprises at least one selected from the groupconsisting of a polyester film, a polyethylene film, a polypropylenefilm, a tri-acetyl cellulose film, a polyvinyl chloride film, apolyvinyl alcohol film, a polyimide film, a cyclo-olefin resin film, apolycarbonate film, a polyethylene terephthalate film, a polyethylenenaphthalate film, a polyether sulfone film, a polyimide film, an epoxyresin film, a phenol resin film, a melamine resin film, a polyurethanefilm, and/or an acrylic resin film.
 6. The display device of claim 1,wherein the plurality of anti-scratch protrusions are arranged in arepeating pattern.
 7. The display device of claim 1, wherein the oneside of the film base extends in a first direction and a seconddirection, and wherein adjacent ones of the plurality of anti-scratchprotrusions are spaced from each other in both the first and seconddirections.
 8. The display device of claim 1, wherein the displayelement layer comprises: a first electrode; an active layer on the firstelectrode; and a second electrode on the active layer.
 9. The displaydevice of claim 8, wherein the active layer is an organic emissionlayer.
 10. The display device of claim 8, wherein the active layer is aliquid crystal layer.
 11. The display device of claim 1, wherein thefilm base is transparent.
 12. The display device of claim 1, furthercomprising an adhesive layer on another side of the film base.
 13. Thedisplay device of claim 1, wherein a shape of each of the plurality ofanti-scratch protrusions is independently selected from the groupconsisting of a lens shape, a pyramidal shape, a conical shape, aprismatic shape, and a cylindrical shape.
 14. The display device ofclaim 1, wherein a height of each of the plurality of anti-scratchprotrusions is from 0.1 μm to 100 μm.
 15. The display device of claim 1,wherein each of the plurality of anti-scratch protrusions has a diameterof from 10 μm to 1mm with a longest radius being on a base side of theanti-scratch protrusion.
 16. The display device of claim 1, wherein adistance between adjacent ones of the plurality of anti-scratchprotrusions is from 10 μm to 1mm.